Atmospheric Particulate Matter (PM): Effects on Biological Mechanisms

What is oxidative stress?

Oxidative stress is a biological imbalance that can lead to health problems. It is characterized by an excessive accumulation of free radicals—unstable molecules—at the expense of antioxidants, which are the molecules responsible for neutralizing free radicals. This oxidative stress is a normal defense mechanism; however, an excess of free radicals can damage the body’s cells and tissues, which will have harmful consequences on health. Oxidative stress and the immune system are closely linked, as they influence one another. Various environmental exposures may modulate oxidative stress and induce changes in immune responses, particularly atmospheric particles. Data from the SEPAGES cohort have allowed us to study the role of fine particles on oxidative stress and immune function.

How to measure fine particulate matter exposure?

Using air pollutant sensors worn by women during pregnancy, two exposure indicators were measured: the mass concentration of airborne particles, which provides information on the quantity of particles inhaled, and the oxidative potential of the particles, a more recent indicator reflecting the toxicity of the particles and, more specifically, their ability to induce oxidative stress in the body.

How to measure oxidative stress and immune response?

Three biomarkers of oxidative stress were measured in urine samples collected during pregnancy. These biomarkers provide information about the oxidation of certain cellular components: lipids (fats) and DNA. Measuring them helps determine whether these cellular components have been damaged. The immune response, meanwhile, is assessed in blood cell samples collected during pregnancy, in which the secretion of interleukins (soluble immune mediators) was measured.

Main results

These studies suggest that exposure to the oxidative potential of fine particulate matter (PM2.5) is associated with an increase in a biomarker of DNA oxidation and with changes in the immune response, including modifications in interleukin-8 and interleukin-17A levels. This finding is interesting because other studies show a link between interleukin-17A and severe forms of asthma

What’s next?

These findings suggest that exposure to fine particulate matter may lead to oxidative stress, which causes DNA damage and modulates immune function. Future studies could examine the role of DNA damage and the identified interleukins on various health parameters, particularly those related to fetal growth and children’s respiratory health.